A programmable controller of the type to which the present invention is directed is known, for example, from DE 36 03 750 or from EP 0 162 373 or, for example, as a programmable controller with the designation Simatic S7-300 or Simatic S7-400 from Siemens AG.
The term programmable controller refers both to a complete device and to individual modules, as they are known, or assemblies, which can be combined to form a complete device.
The programmable controllers of DE 36 03 750 have on a front side, visible to a user or operator, a number of labeling fields. Each labeling field is assigned to an external terminal, so that the user or operator is informed by the label entered in the labeling field about the functionality of the respective external terminal. The label is entered in the labeling field by hand.
The entering of a label in a labeling field is prone to error in a disadvantageous way, because it cannot be ensured that the labeling field assigned to an external terminal is correctly labeled. Moreover, completing a labeling field by hand is labor-intensive.